I was reviewing the Mopar Action article on disc brake conversions and it says almost any MC/Booster can be used after a certain year. I found one in JY off an '87 that looks good and real cheap. But the bolt pattern on the firewall is larger than my existing manual MC. Obviously I would need to drill holes to accomodate the large pattern. Will this work? I also found one on a '77 Volare and the bolt pattern looks identical to the Grand Fury but the MC booster is too rusted.

Thanks

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Sweet Emotion

I'd say the F/J/M booster would be more trouble than it's worth.
The booster has it's own mounting studs (nuts inside the car), right? You'd have to remove the ones in the car, redrill two holes, and redo the bracing so all 4 studs are supported.
Clearance to the cowl flange might be a problem, too; you may have to pound a section flat because this booster sits very close to the firewall.
Then you've got clearance to the steering column, pushrod length, etc., that might cause trouble.
Keep looking

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O==\=/==O

"A mechanic is Somebody."
- Jim Preston

So on the correct booster how does it mount to the firewall? Is there studs on the booster or holes for the existing studs on the firewall?

Thanks.

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Sweet Emotion

A body boosters mount to the existing studs, using an offset bracket that lifts the booster/MC up about 2 inches or so.
The bracket supports a bellcrank that transfers the pushrod movement to the new booster location.
The booster itself uses a smaller diameter diaphragm to prevent hood interference.

_________________
O==\=/==O

"A mechanic is Somebody."
- Jim Preston

I found a picture (link provided) of a MC/booster but no bracket. Is this what it's supposed to look like? Also since I am going from drum to disc I also need the bellcrank bracket inside the firewall, correct? I don't remember reading about that in the Mopar Action article. So the studs in this picture go to the bracket and the bracket mounts to the studs coming out of the firewall. How does the bellcrank bracket mount inside the firewall? That article seems to be lacking in that they imply all you need is a booster and the correct pushrod or an adjustable one. The bellcrank isn't mentioned I don't think. I'll read it again.

Thanks

http://catservices.wrencheadpro.com/Sma ... 506101.jpg

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Sweet Emotion

The bellcrank (for lack of a better term) is contained in the bracket, and both are exposed outside the firewall. The bracket has holes to mount over the studs that the manual master cylinder uses.
Then the booster studs go through the other end of the bracket, as you say.
It has it's own rod that bolts to the pedal, replacing the manual pushrod.
Notice the size of the booster in your picture; smaller than the F/J/M, again for clearance.
I believe the bracket was the same for power discs and power drums; only the M/C changes.
Here's a picture, although not a good one, but you can get the idea;
http://cgi.ebay.com/ebaymotors/ws/eBayI ... 12204&rd=1
The bellcrank is hidden inside the bracket in this picture, but the lower pivot point is visible at the bottom.

_________________
O==\=/==O

"A mechanic is Somebody."
- Jim Preston

I believe Mopar Performance makes a bracket to mount the later aluminum master cylinder. The bolt holes don't line up but the cylinder is so much lighter that racers have been using it for a long time, hence a kit to make it a bolt-in. Unfortunately the kit isn't cheap.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

I ended up getting the MC and booster from the Grand Fury $30 for both. I bought a 4 to 2 bolt bracket from US Car Tool for $35 including shipping. It's just like the Mopar Performance one but cheaper. So my plan for now is to go with manual brakes using the MC from the Grand Fury and shelving the booster for now. The MC is a 1 1/32 inch bore so it should work fine manually according to what I have read.

The picture is helpful. The thing that seems strange is the booster is smaller diameter but the bracket raises it up to about the same hight as F/J/M body booster would be. It seems like the F/J/M body booster could be made to work but that's a later project. Thanks for the help. I'll keep you posted on the results. I'll keep an eye out for a jy donor for the booster and bracket in the picture.